I have quickbooks online and want to add products with barcode

Hello there, Info2364. The barcode scanner isn't supported in QuickBooks Online as this feature is currently available only in QuickBooks Desktop.

However, you can directly find a third party app or products you can integrate with QuickBooks that can help you add a product with barcodes.

Here's how: 

1. Navigate to the Integrations icon beside the Notification icon.
2. Click Find Integrations. 
3. Type keywords or products that supports barcode scanner.

Once you can find an app, click Get Integration Now to connect it.

If you have more further questions, feel free to ask. We're here to help. 

@info2364 

What kind of business do you run? A wholesaler/retailer or manufacturer?

You need to use a 3rd party app to sync with QBO.